JP3811501B2

JP3811501B2 - Hydraulically operated valve device

Info

Publication number: JP3811501B2
Application number: JP50650396A
Authority: JP
Inventors: デニスディーホイクト; ステーブンジェイフンカ; ステーブンエフマイスター
Original assignee: Caterpillar Inc
Current assignee: Caterpillar Inc
Priority date: 1994-08-04
Filing date: 1995-07-10
Publication date: 2006-08-23
Anticipated expiration: 2015-07-10
Also published as: JPH09504074A; EP0722536A1; DE69506219T2; DE69506219D1; WO1996004469A1; US5531192A; EP0722536B1

Description

技術分野
本発明は、一般には内燃エンジン用のバルブ作動装置に関し、より詳しくは特定の間隔で作動装置の速度を制御する油圧手段を使用することにより、通常油圧作動バルブと組合わされる電子制御装置を大幅に簡単にする電子制御油圧作動バルブ装置に関する。
背景技術
電子油圧作動エンジンバルブは、エンジン運転条件の変化に迅速に対応して、エンジンバルブ開閉イベントのタイミングを変化させ、それにより最適化することができるので、機械作動エンジンバルブより有利である。
最近の電子油圧作動装置は、バルブが開位置又は閉位置に近づくとき初期と終期の速度を制御する先進電子制御装置を利用する。しかし、最も進んだ電子制御装置は開発の種々の段階にあり、それゆえ現在生産されている内燃エンジンには適さない。さらに、証明済みの結果ではないが、先進電子制御装置のコストと複雑さは、このような装置により得られる利益を超えることになる。
本発明は、バルブが開位置又は閉位置に近づくときバルブの速度を制御し、それにより電子制御装置がより複雑でなくてすむ油圧手段を利用する。
発明の開示
本発明の１態様では、バルブ作動装置が内燃エンジンに使用される。内燃エンジンは、シリンダーヘッド、及びシリンダーヘッド内に配置されたバルブを有する。バルブは、開位置と閉位置とを有する。バルブ作動装置は、内部にボアを有し、シリンダーヘッドに結合するアクチュエーターヘッド、及びアクチュエーターヘッドのボアに結合するようになった円筒形本体を含む。該本体は、軸方向に延びるボアを有する。プランジャーが、バルブと作動的に組合わさり、またプランジャー表面を有する。プランジャーは、シリンダーヘッドと作動的に組合わさり、プランジャー空洞を形成する。プランジャーは、一部が本体のボア内に摺動可能に配置され、第１位置と第２位置との間を動くことができる。比較的高圧の流体源と比較的低圧の流体源とが、バルブ作動装置に備えられる。プランジャーを第１位置に向かって付勢する手段が備えられる。第１手段が、高圧源からプランジャー空洞へ選択的に流体を流通させ、プランジャーを第２位置に向かって付勢し、バルブが開位置へ動くようにする。付勢手段が、プランジャーを第２位置に向かって押しつけバルブが閉位置へ動くようにするのに応じて、第２手段がプランジャー空洞から排出された流体を低圧源へ流通させる。バルブが開位置と閉位置に近づくと、油圧手段がプランジャーを減速させる。
本発明の他の態様では、内燃エンジンがシリンダーヘッド、及びシリンダーヘッド内に配置されたバルブを有する。バルブは、開位置と閉位置とを有する。内部にボアを有するアクチュエーターヘッドが、シリンダーヘッドに結合する。円筒形本体が、アクチュエーターヘッドのボアに結合する。本体は、軸方向に延びるボアを有する。プランジャーが、バルブと作動的に組合わさり、またプランジャー表面を有する。プランジャーは、シリンダーヘッドと作動的に組合わさり、プランジャー空洞を形成する。プランジャーは、一部が本体のボア内に摺動可能に配置され、第１位置と第２位置との間を動くことができる。比較的高圧の流体源と比較的低圧の流体源とが、バルブ作動装置に備えられる。プランジャーを第１位置に向かって付勢する手段が備えられる。第１手段が、高圧源からプランジャー空洞へ選択的に流体を流通させ、プランジャーを第２位置に向かって付勢し、バルブが開位置へ動くようにする。付勢手段が、プランジャーを第２位置に向かって押しつけバルブが閉位置へ動くようにするのに応じて、第２手段がプランジャー空洞から排出された流体を低圧源へ流通させる。バルブが開位置と閉位置に近づくと、油圧手段がプランジャーを減速させる。
本発明は、バルブの開閉時にプランジャーを減速する油圧手段を使用することにより、バルブの上昇と着座速度を制御する簡単な方法を提供する。本発明は、速度を制御する電子装置を複雑でなくし、それゆえ信頼性がある。
【図面の簡単な説明】
図１は、バルブ作動装置に概略図である。
図２は、バルブが閉位置にあることを示す図１のバルブ作動装置の概略部分断面図である。
図３は、バルブが開位置にあることを示す図１のバルブ作動装置の概略部分断面図である。
図４は、図３の４−４線で囲んだ部分の強調した拡大詳細図である。
図５は、バルブ作動装置のバルブ上昇曲線を示す概略図である。
発明実施のための最良の形態
内燃エンジン12用バルブ作動装置10を図１〜３に示す。エンジン12は、シリンダーヘッド14、及びシリンダーヘッド14内に往復動可能に配置された１つまたはそれ以上のエンジンバルブ16を有する。エンジンバルブ16は図１〜３に一部のみを示し、例えば一連の通常の排気又は吸気ポペットバルブであってもよい。バルブ16は、それぞれ図２に一部を示す第１閉位置と図３に一部を示す第２開位置との間を移動可能である。バルブ16は、螺旋圧縮バネ18等の好適な手段により、第１位置に向かって付勢される。内燃エンジン12は、多行程サイクル又は好適な行程サイクルエンジンであってもよい。明確にするため、エンジン12は１シリンダーのみを有するように記述されるが、バルブ作動装置は、多シリンダーエンジンでも作動するように意図している。
バルブ作動装置10内の内部部品の詳細図を図２〜３に示す。アクチュエーターヘッド20は、直径が変化し軸方向に延びるボア22を有する。さらに、図１により詳細に示すように、アクチュエーターヘッド20は、内部に低圧燃料源26と高圧燃料源28の間を選択的に連通させるレール通路24を有する。高圧燃料源28からの流体の圧力は、1500psiより大きいのが好ましく、3000psiより大きいのがさらに好ましい。低圧燃料源からの流体の圧力は、400psiより小さいのが好ましく、200psiより小さいのがさらに好ましい。円筒形本体30は、複数のＯリング32によりボア22内にシーリングして嵌め込まれ、軸方向に延びるボア36を有する。しかし、本体30をボア22内に嵌め込むのに、どのような好適な結合又はシーリング手段を使用してもよい。好適な型のブリッジ46が、アクチュエーターヘッド20の溝48内に配置され、本体30に隣接する。ブリッジ46は、本体30のボア36と軸方向に整列した所定の長さのボア50を有する。プランジャー表面58を有するプランジャー54の端部60が、ブリッジ46のボア50内にしっかり嵌め込まれ、プランジャー54の一部が他端部62で本体30のボア36内に摺動可能に配置される。プランジャー54の他端部62は、プランジャー表面58から所定の角度で広がる円錐台形64を有し、これは図４により詳細に見ることができる。プランジャー54は、ブリッジ46と一体に成形してもよく、別体でブリッジ46にプレス嵌め等で結合してもよい。プランジャー54は、バルブ16と作動的に組合わさり、第１位置と第２位置との間を動くことができる。プランジャー54の第２位置へ向かう動きにより、バルブ16が開位置へ動く。プランジャー54は、螺旋バネ18により第１位置に付勢される。ブリッジ46を使用せずにプランジャー54がエンジンバルブ16を直接作動させるように使用してもよい。このように、プランジャー54はエンジンバルブ16と一体に成形しても、別体でエンジンバルブ16に隣接して配置してもよい。
低圧流体をブリッジ46へ流通させる手段68が、端部60に近接して設けられる。流通させる手段68は、ブリッジ46内に配置された一対のオリフィス69、及びオリフィス69とブリッジ46を通りプランジャー54内へ延びる一対の結合通路70を含む。縦方向ボア74が、プランジャー54内へ所定の距離だけ延び、ブリッジ46内の結合通路70と流体接続される。オリフィス通路80が、縦方向ボア74から外方向へ延びる。プランジャー54の端部60に近接して、クロスボア84が本体30の下端部90を通って延びる。クロスボア84は、本体30とアクチュエーターヘッド20の間に形成された下側環状空洞94に結合され、そこと流体接続される。下側環状空洞94は、アクチュエーターヘッド20のレール24に結合した通路96を通って、低圧流体源26と接続される。クロスボア84は、オリフィス通路80に対して所定の位置をとる。ブリッジ46の１対の大きなボア106,107内の１対の油圧隙間調節機100,102が、それぞれ１対の保持リング108,110等の好適な手段でブリッジ46に固定される。隙間調節機100,102は、オリフィス69及び結合通路70と流体接続し、エンジンバルブ16に隣接する。しかし、隙間調節機100,102は、使用する内部の設計によってオリフィス69があってもなくてもよい。
プラグ120がアクチュエーターヘッド20に結合し、ネジ止め又はプレス嵌め等の好適な手段でボア50の上端部124にシーリングして嵌め込まれる。ボア50内のプラグ120とプランジャー表面58の間に、プランジャー空洞130が形成される。プラグ120はボア50内に嵌め込まれ、プランジャー空洞130を形成するように示されるが、シリンダーヘッド14はボア50にシーリングして嵌め込まれてもよい。それゆえ、プランジャー空洞130はシリンダーヘッド14とプランジャー表面58の間の形成される。
高圧流体源からプランジャー空洞130へ選択的に流通する第１手段140が設けられ、プランジャー54を第２位置へ向かって付勢する。第１流通手段140は、第２位置へ向かう動きの初期に、高圧流体源とプランジャー空洞130の間の第１流路148を形成する手段144を含む。手段144は、さらに第２位置へ向かう動きの終期に、高圧流体源とプランジャー空洞130の間に第２流路152を形成する。制御弁好ましくはスプール弁156が、高圧レール通路24を通って、第1,第２流路148,152へ流体を流通させる。スプール弁156は、１対の螺旋圧縮バネ（図示せず）により第１位置へ向かって付勢され、該バネ（図示せず）に抗してアクチュエーター158により第２位置へ動かされる。この実施例ではアクチュエーター158は圧電モーターであるが、アクチュエーター158はどのような好適な型でもよい。圧電モーター158は、通常のオン／オフ電圧パターンを有する制御ユニットにより駆動される。
第１流通手段の第１流路148は、本体30とアクチュエーターヘッド20の間に形成された環状室160を含む。主ポート164が、本体30内に環状室160と流体接続して形成され、また所定の直径を有する。プランジャー54と本体30の間に環状空洞168が形成され、また所定の長さと主ポート164に対して所定の位置を有する。プランジャー54が第１位置と第２位置の間を動く過程の一部で、環状空洞168は主ポート164と流体接続される。プランジャー54内に通路170が配置され、一部が環状空洞168を横切り、そこと流体接続する。第１チェック弁174がプランジャー54のボア176内に着座し、内部に通路170と流体接続するオリフィス178を有する。第１チェック弁174は開位置と閉位置を有し、オリフィス178は所定の直径を有する。ストップ部材180がプランジャー54の他のボア182内に着座し、第１チェック弁174から所定の距離で配置される。ストップ部材180は、軸方向に延びるボアを有し、オリフィス178をプランジャー空洞130と流体接続し、また逃げを付けた外径を有する。第１チェック弁174内の弁174とストップ部材180の間に戻りバネ183が配置される。
第１流通手段140の第２流路152は、主ポート164の直径より小さい直径を有する制限ポート190を含む。プランジャー54が第１位置と第２位置の間を動く過程の一部で、制限ポート190は環状室160を環状空洞168に流体接続する。
螺旋バネ18に応じてプランジャー空洞130から低圧流体源26へ排出される流体を選択的に流通させる第２手段200が設けられ、プランジャー54を第１位置へ向かって付勢する。第２流通手段200は、第２位置から第１位置へ向かう動きの初期に、プランジャー空洞130と低圧流体源26の間の第１流路208を形成する手段204を含む。手段144は、さらに第２位置から第１位置へ向かう動きの終期に、プランジャー空洞130と低圧流体源26の間に第２流路210を形成する。スプール弁156は、第1,第２流路208,210を通って低圧レールへ選択的に流体を流通させる。
第２流通手段200の第１流路208は、本体30のボア216内に着座する第２チェック弁214を含み、第２チェック弁214の一部が環状室160内へ延びる。第２チェック弁214は、開位置と閉位置を有する。小さな円錐形戻りバネ（図示せず）が、第２チェック弁214内に配置される。出口通路218が、本体30内の第２チェック弁214とプランジャー54の間に形成される。プランジャー54が第２位置と第１位置の間を動く一部で、第２チェック弁が開位置にあるとき、出口通路218はプランジャー空洞130と環状室160を流体接続する。
第２流通手段200の第２流路210は、プランジャー54が第２位置と第１位置の間を動く過程の一部で、低圧源26に流体接続されるオリフィス178を含む。
バルブ16が開位置に近づくときプランジャー54を減速する第１油圧手段230が設けられる。第１油圧手段230は、プランジャー54が第１位置と第２位置の間を動く過程の一部で、高圧流体源28から主ポート164を通り環状空洞168への流体接続を制限すること、及びプランジャー54が第１位置と第２位置の間を動く別のとき、高圧流体源28から主ポート164を通り環状空洞168への流体接続をブロックすることを含む。バルブ16が閉位置へ近づくとプランジャー54を減速する第２油圧手段240が設けられる。第２油圧手段240は、円錐台形のプランジャー54の端部62を含み、該端部がプランジャー空洞168から出口通路218を通って低圧流体源26への流体接続を制限し、プランジャー空洞168から出口通路218を通って低圧流体源26への流体接続をブロックする。
産業上の利用可能性
よりよく理解するため、次の順番はプランジャー54が第１位置で、それゆえバルブが閉（即ち着座）位置で始まる。図１を参照すると、バルブを開く順番を開始するには、制御ユニットからの電圧が圧電モーター158へ送られ、それが次にスプール弁156を公知の方法で第１位置Ｐ１から第２位置Ｐ２へ駆動する。スプール弁156の第１位置Ｐ１から第２位置Ｐ２への移動が、低圧流体源26とプランジャー空洞130の間の連通を閉じ、高圧流体源28とプランジャー空洞130の間の連通を開く。
図２をより詳しく参照すると、プランジャー54の第１位置から第２位置への移動の初期部分で、高圧流体源28からの高圧流体は、第１流路148を通ってプランジャー空洞130へ流通する。高圧流体が、第１チェック弁174をシートから離し、高圧流体の大部分がストップ部材180の逃げを付けた外径を通って高速で第１チェック弁174の周りからプランジャー空洞130へ入るようにする。
プランジャー空洞130が高圧流体で満たされると、プランジャー54が急速に下方へ動き、バネ18の力に抗してバルブ16を開く。プランジャー54が下方へ動くと、主ポート164に対する環状空洞168の位置は一定に変化する。環状空洞168の下方への動きが、環状空洞168と制限ポート190の間を流体接続し、それにより高圧流体が第1,第２流路148,152の両方を通ってプランジャー空洞130へ入ることができるようにする。
図３に示すように、プランジャーの動きの終期に環状空洞168が主ポート164を過ぎて動くと、プランジャー54の外周部により流体接続は制限され、最終的にブロックされ、高圧流体源28とプランジャー空洞130の間の流体接続は、制限ポート190を通るものだけとなる。制限ポート190の直径は主ポート174より小さいので、プランジャー54の下方への動きはおそくなり、それによりバルブ16は全開位置に到達するときに減速される。
環状空洞168が制限ポート190を過ぎて動くと、プランジャー54の外周部により流体接続は制限され、最終的にブロックされ、それによりプランジャー54がバルブ16を最大上昇位置に保持することができるようにする。装置内で漏れが起こると、プランジャー54は上方へ動き、制限ポート190を少し再度開き、それゆえプランジャー空洞130を再び満たし、プランジャー54を下方へ戻す。次に、プランジャー54の小さい動きが制限ポート190を開閉することにより、バルブ16の開位置が最大上昇位置の近くに固定される。このとき、第１チェック弁174の戻りバネ183が、弁174をそのシートへ戻す。制限ポート190は特定の設計に限る必要はなく、そうすると大きな直径のプランジャー54又は力の強いバネ18を使用する等で、プランジャー54を最大上昇で急速に停止することができる。
再び図１を参照すると、バルブを閉じる順番を開始するには、制御ユニットからの電圧が圧電モーター158から取り除かれ、それが次にスプール弁156を公知の方法で第２位置Ｐ２から第１位置Ｐ１へ戻ることができるようにする。スプール弁156の第２位置Ｐ２から第１位置Ｐ１への移動が、高圧流体源28とプランジャー空洞130の間の連通を閉じ、低圧流体源26とプランジャー空洞130の間の連通を開く。この段階で、バネ18の位置エネルギーはエンジンバルブ16を上方へ動かす運動エネルギーに変わる。
図３をより詳しく参照すると、そのとき低圧流体は環状室160内にあるので、プランジャー空洞130内の高圧流体が、第２チェック弁214をシートから離す。第２チェック弁214がシートから離れると、プランジャー空洞130内の大部分の流体は第１流路208を通って低圧流体源26へ戻ることができる。プランジャーの第２位置から第１位置への動きの終期に、オリフィス178が環状室160と流通するので、プランジャー空洞130内の一部の流体は第２流路を通って低圧流体源26へ戻ることができる。
プランジャー54の円錐台形の端部62が出口通路218を過ぎて動くと、低圧流体26への流体接続は次第に制限され、最終的にブロックされ、バルブ16は全閉位置即ち着座位置に到達するときに減速される。図２に示すように、いったん出口通路218が完全にブロックされると、プランジャー空洞130から低圧流体室26への流体接続は、オリフィス178を通るものだけとなる。第１チェック弁174は着座しているので、流体接続はオリフィス178を通ってのみ起こり、実質的に第１チェック弁174の周りにさらに流体接続しないようにする。それゆえ、オリフィス178の直径が小さい方が、最終着座速度はよりよく制御される。
さらに、スプール弁156がＰ１位置にあり低圧流体源26と結合されると、流体はオリフィス69を通って油圧調節機100,102へ流通する。オリフィス69は通路70と連通し、隙間調節機100,102に許される最大圧力を制御する。しかし、スプール弁156がＰ２位置に動くと、プランジャー54は下方へ動き、オリフィス通路80がクロスボア84を過ぎて動き、低圧流体源26から調節機100,102への流体接続を次第に制限し、最終的にブロックする。
図５は、本発明の設計に関する最適なバルブ上昇曲線を示す。点Ａは、スプール弁156をＰ１からＰ２へ動かすスプール弁156への初期の制御信号に関する。点Ｂでは、第１チェック弁174がシートから離れ、その結果バルブ16が急速に開く。点Ｃで、主ポート164をブロックする。曲線Ｄは、制限ポート190を通ってプランジャー空洞130への流体接続を制限することに関する。点Ｅで、制限ポート190をブロックする。線Ｆは、最大バルブ上昇量に関する。点Ｇは、スプール弁156をＰ２からＰ１へ動かすスプール弁156への終期の制御信号に関する。点Ｈは、第２チェック弁214を通る急速な放出に関する。曲線ＩとＪは、プランジャー54の円錐台形端部62が、プランジャー空洞130から出口通路218を通る流体接続を制限することに関する。点Ｋは、プランジャー空洞130から出口通路218を通る流体接続を制限し、プランジャー空洞130から低圧流体源26への流体接続はオリフィス178を通るもののみとなるようにして達成される微妙な速度制御に関する。
上述のことから、バルブの開閉時にプランジャー速度を減速するため油圧手段を使用することにより、バルブの上昇とバルブの着座を制御する簡単な方法を与える。本発明は、速度を制御するのに高価な又は複雑な電子装置に頼らず、そのためより信頼性が高い。 TECHNICAL FIELD The present invention relates generally to valve actuation devices for internal combustion engines, and more particularly in combination with hydraulic actuation valves by using hydraulic means that control the speed of the actuation device at specific intervals. The present invention relates to an electronically controlled hydraulically operated valve device that greatly simplifies the electronic control device.
BACKGROUND ART Electro-hydraulic engine valves are more responsive to changes in engine operating conditions and can be optimized by changing the timing of engine valve opening and closing events. It is advantageous.
Modern electrohydraulic actuators utilize advanced electronic controllers that control the initial and final speed as the valve approaches the open or closed position. However, the most advanced electronic control units are at various stages of development and are therefore not suitable for currently produced internal combustion engines. In addition, although not a proven result, the cost and complexity of advanced electronic control devices exceeds the benefits obtained by such devices.
The present invention utilizes hydraulic means that controls the speed of the valve as it approaches the open or closed position, thereby reducing the complexity of the electronic controller.
DISCLOSURE OF THE INVENTION In one aspect of the invention, a valve actuator is used in an internal combustion engine. The internal combustion engine has a cylinder head and a valve disposed in the cylinder head. The valve has an open position and a closed position. The valve actuator includes an actuator head having a bore therein and coupled to the cylinder head and a cylindrical body adapted to be coupled to the bore of the actuator head. The body has a bore extending in the axial direction. A plunger is operatively associated with the valve and has a plunger surface. The plunger is operatively associated with the cylinder head to form a plunger cavity. The plunger is partially slidably disposed within the bore of the body and can move between a first position and a second position. A relatively high pressure fluid source and a relatively low pressure fluid source are provided in the valve actuator. Means are provided for biasing the plunger toward the first position. The first means selectively allows fluid to flow from the high pressure source to the plunger cavity, biasing the plunger toward the second position and causing the valve to move to the open position. In response to the biasing means pressing the plunger toward the second position and causing the valve to move to the closed position, the second means causes fluid discharged from the plunger cavity to flow to the low pressure source. As the valve approaches the open and closed positions, the hydraulic means decelerates the plunger.
In another aspect of the invention, an internal combustion engine has a cylinder head and a valve disposed in the cylinder head. The valve has an open position and a closed position. An actuator head having a bore therein is coupled to the cylinder head. A cylindrical body is coupled to the bore of the actuator head. The main body has a bore extending in the axial direction. A plunger is operatively associated with the valve and has a plunger surface. The plunger is operatively associated with the cylinder head to form a plunger cavity. The plunger is partially slidably disposed within the bore of the body and can move between a first position and a second position. A relatively high pressure fluid source and a relatively low pressure fluid source are provided in the valve actuator. Means are provided for biasing the plunger toward the first position. The first means selectively allows fluid to flow from the high pressure source to the plunger cavity, biasing the plunger toward the second position and causing the valve to move to the open position. In response to the biasing means pressing the plunger toward the second position and causing the valve to move to the closed position, the second means causes fluid discharged from the plunger cavity to flow to the low pressure source. As the valve approaches the open and closed positions, the hydraulic means decelerates the plunger.
The present invention provides a simple method of controlling valve lift and seating speed by using hydraulic means to decelerate the plunger when opening and closing the valve. The present invention reduces the complexity of the electronic device that controls the speed and is therefore reliable.
[Brief description of the drawings]
FIG. 1 is a schematic diagram of a valve actuator.
FIG. 2 is a schematic partial cross-sectional view of the valve actuator of FIG. 1 showing the valve in the closed position.
FIG. 3 is a schematic partial cross-sectional view of the valve actuator of FIG. 1 showing the valve in the open position.
FIG. 4 is an enlarged detailed view with emphasis on the portion surrounded by line 4-4 in FIG.
FIG. 5 is a schematic view showing a valve rising curve of the valve operating device.
BEST MODE FOR CARRYING OUT THE INVENTION A valve operating device 10 for an internal combustion engine 12 is shown in FIGS. The engine 12 includes a cylinder head 14 and one or more engine valves 16 that are reciprocally disposed within the cylinder head 14. The engine valve 16 is only partially shown in FIGS. 1-3 and may be, for example, a series of normal exhaust or intake poppet valves. Each of the valves 16 is movable between a first closed position partially shown in FIG. 2 and a second open position partially shown in FIG. The valve 16 is biased toward the first position by suitable means such as a helical compression spring 18. The internal combustion engine 12 may be a multi-stroke cycle or a suitable stroke cycle engine. For clarity, the engine 12 is described as having only one cylinder, but the valve actuator is intended to work with a multi-cylinder engine.
Detailed views of the internal components within the valve actuator 10 are shown in FIGS. The actuator head 20 has a bore 22 that changes in diameter and extends in the axial direction. Further, as shown in more detail in FIG. 1, the actuator head 20 has a rail passage 24 that selectively communicates between the low pressure fuel source 26 and the high pressure fuel source 28 therein. The pressure of the fluid from the high pressure fuel source 28 is preferably greater than 1500 psi, and more preferably greater than 3000 psi. The pressure of the fluid from the low pressure fuel source is preferably less than 400 psi, more preferably less than 200 psi. The cylindrical main body 30 has a bore 36 that extends in the axial direction and is fitted in the bore 22 by a plurality of O-rings 32. However, any suitable coupling or sealing means may be used to fit the body 30 into the bore 22. A suitable type of bridge 46 is disposed in the groove 48 of the actuator head 20 and is adjacent to the body 30. The bridge 46 has a bore 50 of a predetermined length that is axially aligned with the bore 36 of the body 30. The end 60 of the plunger 54 with the plunger surface 58 is securely fitted into the bore 50 of the bridge 46 and a portion of the plunger 54 is slidably disposed within the bore 36 of the body 30 at the other end 62. Is done. The other end 62 of the plunger 54 has a frustoconical shape 64 extending at a predetermined angle from the plunger surface 58, which can be seen in more detail in FIG. The plunger 54 may be formed integrally with the bridge 46, or may be separately connected to the bridge 46 by press fitting or the like. Plunger 54 is operatively associated with valve 16 and is movable between a first position and a second position. Movement of plunger 54 toward the second position causes valve 16 to move to the open position. The plunger 54 is biased to the first position by the helical spring 18. Plunger 54 may be used to actuate engine valve 16 directly without using bridge 46. As described above, the plunger 54 may be formed integrally with the engine valve 16 or may be separately disposed adjacent to the engine valve 16.
Means 68 for circulating the low pressure fluid to the bridge 46 is provided proximate the end 60. The means 68 for flow includes a pair of orifices 69 disposed in the bridge 46 and a pair of coupling passages 70 extending through the orifice 69 and the bridge 46 and into the plunger 54. A longitudinal bore 74 extends a predetermined distance into the plunger 54 and is fluidly connected to the coupling passage 70 in the bridge 46. An orifice passage 80 extends outwardly from the longitudinal bore 74. Proximate to end 60 of plunger 54, cross bore 84 extends through lower end 90 of body 30. The cross bore 84 is coupled to and fluidly connected to a lower annular cavity 94 formed between the body 30 and the actuator head 20. The lower annular cavity 94 is connected to the low pressure fluid source 26 through a passage 96 coupled to the rail 24 of the actuator head 20. The cross bore 84 takes a predetermined position with respect to the orifice passage 80. A pair of hydraulic clearance adjusters 100, 102 within a pair of large bores 106, 107 in the bridge 46 are secured to the bridge 46 by suitable means such as a pair of retaining rings 108, 110, respectively. The clearance adjusters 100 and 102 are in fluid connection with the orifice 69 and the coupling passage 70 and are adjacent to the engine valve 16. However, the gap adjusters 100 and 102 may or may not have the orifice 69 depending on the internal design used.
A plug 120 is coupled to the actuator head 20 and is sealed and fitted into the upper end 124 of the bore 50 by suitable means such as screwing or press fitting. A plunger cavity 130 is formed between the plug 120 in the bore 50 and the plunger surface 58. Although the plug 120 is shown fitted into the bore 50 to form the plunger cavity 130, the cylinder head 14 may be sealed and fitted into the bore 50. Therefore, the plunger cavity 130 is formed between the cylinder head 14 and the plunger surface 58.
A first means 140 is provided for selectively flowing from the high pressure fluid source to the plunger cavity 130 to bias the plunger 54 toward the second position. The first flow means 140 includes means 144 that form a first flow path 148 between the high pressure fluid source and the plunger cavity 130 at the beginning of movement toward the second position. The means 144 further forms a second flow path 152 between the high pressure fluid source and the plunger cavity 130 at the end of movement toward the second position. A control valve, preferably a spool valve 156, circulates fluid through the high pressure rail passage 24 to the first and second flow paths 148,152. The spool valve 156 is biased toward the first position by a pair of helical compression springs (not shown), and is moved to the second position by an actuator 158 against the springs (not shown). In this embodiment, the actuator 158 is a piezoelectric motor, but the actuator 158 may be of any suitable type. The piezoelectric motor 158 is driven by a control unit having a normal on / off voltage pattern.
The first flow path 148 of the first flow means includes an annular chamber 160 formed between the main body 30 and the actuator head 20. A main port 164 is formed in the body 30 in fluid connection with the annular chamber 160 and has a predetermined diameter. An annular cavity 168 is formed between the plunger 54 and the body 30 and has a predetermined length and a predetermined position with respect to the main port 164. As part of the process of moving the plunger 54 between the first and second positions, the annular cavity 168 is fluidly connected to the main port 164. A passage 170 is disposed within the plunger 54 and a portion traverses the annular cavity 168 and is in fluid connection therewith. A first check valve 174 sits in the bore 176 of the plunger 54 and has an orifice 178 in fluid communication with the passage 170 therein. The first check valve 174 has an open position and a closed position, and the orifice 178 has a predetermined diameter. A stop member 180 is seated in the other bore 182 of the plunger 54 and is disposed at a predetermined distance from the first check valve 174. Stop member 180 has an axially extending bore and fluidly connects orifice 178 with plunger cavity 130 and has an outer diameter with relief. A return spring 183 is disposed between the valve 174 and the stop member 180 in the first check valve 174.
The second flow path 152 of the first flow means 140 includes a restriction port 190 having a diameter smaller than that of the main port 164. As part of the process of the plunger 54 moving between the first and second positions, the restriction port 190 fluidly connects the annular chamber 160 to the annular cavity 168.
Second means 200 is provided to selectively circulate fluid discharged from the plunger cavity 130 to the low pressure fluid source 26 in response to the helical spring 18 and bias the plunger 54 toward the first position. The second flow means 200 includes means 204 that forms a first flow path 208 between the plunger cavity 130 and the low pressure fluid source 26 at the beginning of movement from the second position to the first position. The means 144 further forms a second flow path 210 between the plunger cavity 130 and the low pressure fluid source 26 at the end of the movement from the second position to the first position. The spool valve 156 selectively allows fluid to flow through the first and second flow paths 208 and 210 to the low pressure rail.
The first flow path 208 of the second flow means 200 includes a second check valve 214 seated in the bore 216 of the main body 30, and a part of the second check valve 214 extends into the annular chamber 160. The second check valve 214 has an open position and a closed position. A small conical return spring (not shown) is disposed in the second check valve 214. An outlet passage 218 is formed between the second check valve 214 in the body 30 and the plunger 54. The outlet passage 218 fluidly connects the plunger cavity 130 and the annular chamber 160 when the plunger 54 is part of the movement between the second position and the first position and the second check valve is in the open position.
The second flow path 210 of the second flow means 200 includes an orifice 178 that is fluidly connected to the low pressure source 26 as part of the process of the plunger 54 moving between the second position and the first position.
First hydraulic means 230 is provided that decelerates the plunger 54 when the valve 16 approaches the open position. The first hydraulic means 230 restricts the fluid connection from the high pressure fluid source 28 through the main port 164 to the annular cavity 168 as part of the process of the plunger 54 moving between the first position and the second position. And when the plunger 54 moves between the first position and the second position, including blocking the fluid connection from the high pressure fluid source 28 through the main port 164 to the annular cavity 168. A second hydraulic means 240 is provided that decelerates the plunger 54 when the valve 16 approaches the closed position. The second hydraulic means 240 includes an end 62 of a frustoconical plunger 54 that restricts the fluid connection from the plunger cavity 168 through the outlet passage 218 to the low pressure fluid source 26, and the plunger cavity Block fluid connection from low pressure fluid source 26 through outlet passage 218 from 168.
Industrial Applicability For better understanding, the next sequence begins with the plunger 54 in the first position and hence the valve in the closed (i.e. seated) position. Referring to FIG. 1, to initiate the sequence of opening the valves, a voltage from the control unit is sent to the piezoelectric motor 158, which then causes the spool valve 156 to move from the first position P1 to the second position P2 in a known manner. Drive to. Movement of the spool valve 156 from the first position P1 to the second position P2 closes the communication between the low pressure fluid source 26 and the plunger cavity 130 and opens the communication between the high pressure fluid source 28 and the plunger cavity 130.
Referring more particularly to FIG. 2, during the initial portion of movement of the plunger 54 from the first position to the second position, high pressure fluid from the high pressure fluid source 28 passes through the first flow path 148 to the plunger cavity 130. Circulate. The high pressure fluid moves the first check valve 174 away from the seat so that the majority of the high pressure fluid enters the plunger cavity 130 around the first check valve 174 at high speed through the escaped outer diameter of the stop member 180. To.
When the plunger cavity 130 is filled with high pressure fluid, the plunger 54 rapidly moves downward and opens the valve 16 against the force of the spring 18. As the plunger 54 moves downward, the position of the annular cavity 168 relative to the main port 164 changes constantly. The downward movement of the annular cavity 168 fluidly connects between the annular cavity 168 and the restriction port 190 so that high pressure fluid enters the plunger cavity 130 through both the first and second flow paths 148,152. It can be so.
As shown in FIG. 3, when the annular cavity 168 moves past the main port 164 at the end of the plunger movement, the outer periphery of the plunger 54 restricts the fluid connection and eventually blocks the high pressure fluid source 28. And the plunger cavity 130 has only a fluid connection through the restriction port 190. Since the diameter of the restriction port 190 is smaller than the main port 174, the downward movement of the plunger 54 is slowed, whereby the valve 16 is decelerated when it reaches the fully open position.
As the annular cavity 168 moves past the restriction port 190, the fluid connection is restricted and eventually blocked by the outer periphery of the plunger 54, thereby allowing the plunger 54 to hold the valve 16 in the maximum raised position. Like that. When a leak occurs in the device, the plunger 54 moves upward and reopens the restriction port 190 slightly, thus refilling the plunger cavity 130 and returning the plunger 54 downward. Next, a small movement of the plunger 54 opens and closes the restriction port 190, thereby fixing the open position of the valve 16 near the maximum raised position. At this time, the return spring 183 of the first check valve 174 returns the valve 174 to its seat. The restriction port 190 need not be limited to a particular design, so that the plunger 54 can be rapidly stopped at maximum elevation, such as by using a large diameter plunger 54 or a strong spring 18.
Referring again to FIG. 1, to begin the sequence of closing the valves, the voltage from the control unit is removed from the piezoelectric motor 158, which then causes the spool valve 156 to move from the second position P2 to the first position in a known manner. Enable to return to P1. Movement of the spool valve 156 from the second position P2 to the first position P1 closes the communication between the high pressure fluid source 28 and the plunger cavity 130 and opens the communication between the low pressure fluid source 26 and the plunger cavity 130. At this stage, the potential energy of the spring 18 changes to kinetic energy that moves the engine valve 16 upward.
Referring more particularly to FIG. 3, since the low pressure fluid is now in the annular chamber 160, the high pressure fluid in the plunger cavity 130 moves the second check valve 214 away from the seat. When the second check valve 214 moves away from the seat, most of the fluid in the plunger cavity 130 can return to the low pressure fluid source 26 through the first flow path 208. At the end of the movement of the plunger from the second position to the first position, the orifice 178 is in fluid communication with the annular chamber 160 so that some fluid in the plunger cavity 130 passes through the second flow path and the low pressure fluid source 26. You can go back to
As the frustoconical end 62 of the plunger 54 moves past the outlet passage 218, the fluid connection to the low pressure fluid 26 is gradually limited and eventually blocked, and the valve 16 reaches the fully closed or seated position. When you are slowed down. As shown in FIG. 2, once the outlet passage 218 is completely blocked, the fluid connection from the plunger cavity 130 to the low pressure fluid chamber 26 is only through the orifice 178. Since the first check valve 174 is seated, fluid connection occurs only through the orifice 178, substantially preventing further fluid connection around the first check valve 174. Therefore, the final seating speed is better controlled when the diameter of the orifice 178 is smaller.
Further, when the spool valve 156 is in the P1 position and coupled to the low pressure fluid source 26, fluid flows through the orifice 69 to the hydraulic regulators 100,102. The orifice 69 communicates with the passage 70 and controls the maximum pressure allowed for the clearance adjusters 100,102. However, when the spool valve 156 moves to the P2 position, the plunger 54 moves downward and the orifice passage 80 moves past the crossbore 84, gradually limiting the fluid connection from the low pressure fluid source 26 to the regulators 100, 102, and eventually To block.
FIG. 5 shows the optimal valve rise curve for the design of the present invention. Point A relates to the initial control signal to the spool valve 156 that moves the spool valve 156 from P1 to P2. At point B, the first check valve 174 leaves the seat so that the valve 16 opens rapidly. At point C, main port 164 is blocked. Curve D relates to restricting the fluid connection through the restricting port 190 to the plunger cavity 130. At point E, the restricted port 190 is blocked. Line F relates to the maximum valve lift. Point G relates to the final control signal to the spool valve 156 that moves the spool valve 156 from P2 to P1. Point H relates to rapid discharge through the second check valve 214. Curves I and J relate to the frustoconical end 62 of the plunger 54 limiting the fluid connection from the plunger cavity 130 through the outlet passage 218. Point K limits the fluid connection from the plunger cavity 130 through the outlet passage 218 and is a subtle effect achieved so that the fluid connection from the plunger cavity 130 to the low pressure fluid source 26 is only through the orifice 178. It relates to speed control.
From the above, a simple method of controlling valve lift and valve seating is provided by using hydraulic means to decelerate the plunger speed when opening and closing the valve. The present invention does not rely on expensive or complex electronic devices to control speed and is therefore more reliable.

Claims

In an electronically controlled valve actuator (10) used in an internal combustion engine (12) having a cylinder head (14) and a valve (16) disposed in the cylinder head (14) and having an open position and a closed position,
An actuator head (20) coupled to the cylinder head (14) and having a bore (22) therein;
A cylindrical body (30) adapted to couple into the bore (22) of the actuator head (20) and having an axially extending bore (36);
Operatively associated with the valve (16) , having an end (62) having a plunger surface (58) , a portion of which is slidably disposed within the bore (36) of the body (30) A plunger (54) that is movable between a first plunger position and a second plunger position ;
A plunger cavity (130) formed in the bore (36) by the cylindrical body (30) and the plunger surface (58);
A relatively high pressure fluid source (28);
A relatively low pressure fluid source (26);
Biasing means (18) for biasing the plunger (54) toward the first plunger position ;
Electronic control switched between a first valve position (P1) communicating with the relatively low pressure fluid source (26) and a second valve position (P2) communicating with the relatively high pressure fluid source (28). Valve means (156,158);
When the electronic control valve means (156, 158) is switched to the second valve position (P2) to move the valve (16) to the open position, the plunger (54) is moved to the second position. First flow means (140) for selectively flowing fluid from the high pressure fluid source (28) into the plunger cavity (130) so as to bias toward the plunger position ;
When the electronic control valve means (156, 158) is switched to the first valve position (P1) so that the valve (16) is moved to the closed position, the plan by the biasing means (18) Second flow means (200) for selectively flowing the fluid discharged from the plunger cavity (130) to the low-pressure fluid source (26) under a biasing force that directs the jar (54) toward the first plunger position. )When,
Hydraulic means (240) for decelerating the plunger (54) when the valve (16) approaches the closed position, and
The second flow means (200) is formed between the plunger cavity (130) and the low pressure fluid source (26) at the beginning of the movement of the plunger (56) toward the first plunger position. And a second flow formed between the plunger cavity (130) and the low pressure fluid source (26) at the end of the movement of the plunger (56) towards the first plunger position. Road (210) and
When the valve (16) approaches the closed position, the hydraulic means (240) first passes from the plunger cavity (130) to the low pressure fluid source (26) via the first flow path (208). The plunger (54) is decelerated by restricting the fluid connection, and then the plunger (54) is decelerated by blocking so that only the second flow path (210) is fluidly connected. The valve actuator (10) .

The first flow path (208) of the second flow means (200) includes an outlet passage (218) formed in the main body (30) and opened and closed by the movement of the plunger (54). The restriction and blocking of fluid connection from the jar cavity (130) to the low pressure fluid source (26) via the first flow path (208) is performed by opening and closing the outlet passage (218). The valve actuator (10) .

The end (62) of the plunger (54) has a frustoconical shape (64), and the low pressure fluid source (26) from the plunger cavity (130) via the first flow path (208). Restricting and blocking the fluid connection to the end is performed by the end (62) having the frustoconical shape (64) moving past the outlet passage (218) to open and close the outlet passage (218). The valve actuator (10) according to 2 .

The second flow path (210) of the second flow means (200) includes a first check valve (174) seated in a bore (176) of the plunger (54), and the first check valve ( 174) includes an orifice (178) formed in fluid communication with the passage (170) and the first check valve (174) substantially restricts fluid flow in the direction toward the plunger cavity (130). 4. A valve actuation system (10) according to claim 3, having a closed position that does not open and a closed position that substantially restricts fluid flow in the opposite direction.

The first flow path (208) of the second flow means (200) includes an annular chamber (160) formed between the actuator head (20) and the main body (30), and the main body (30). A second check valve (214) disposed in the annular chamber (160) and seated on a part of the annular chamber (160), the second check valve (214) including the annular chamber (160) and the low-pressure fluid source (26). The valve operating device (10) according to claim 4, wherein the valve operating device (10) is openable and closable when fluidly connected.

Furthermore, provided with hydraulic means (230) for decelerating the plunger (54) when the valve (16) approaches the open position,
The first flow means (140) is formed between the high pressure fluid source (28) and the plunger cavity (130) at the beginning of the movement of the plunger (56) toward the second plunger position. A first flow path (148) and a second flow formed between the high pressure fluid source (28) and the plunger cavity (130) at the end of the movement of the plunger (56) toward the second plunger position. Road (152),
When the valve (16) approaches the open position, the hydraulic means (230) first moves from the high-pressure fluid source (28) to the plunger cavity (130) via the first flow path (148). The plunger (54) is decelerated by restricting the fluid connection thereof, and then the plunger (54) is decelerated by blocking so that only the second flow path (152) is fluidly connected. The valve actuator (10) according to any one of claims 5 to 5.

The hydraulic means (230) blocks fluid connection through the first flow path (148) when the valve (16) approaches the open position, and then from the high-pressure fluid source (28) to the second The plunger (54) is decelerated by restricting the fluid connection to the plunger cavity (130) via the flow path (152), and then the valve (16) is reached to the maximum open position by blocking. 7. A valve actuating device (10) according to claim 6, wherein the valve actuating device (10) is adapted.

The first flow path (148) of the first flow means (140) includes a main port (164) formed in the main body (30) and opened and closed by movement of the plunger (54), and the high pressure The restriction and blocking of fluid connection from the fluid source (28) to the plunger cavity (130) via the first flow path (148) is performed by opening and closing the main port (164). Valve actuator (10).

The second flow path (152) of the first flow means (140) includes a restriction port (190) formed in the main body (30) and opened and closed by movement of the plunger (54), and the high pressure The restriction and blocking of fluid connection from the fluid source (28) to the plunger cavity (130) via the second flow path (152) are performed by opening and closing the restriction port (190). Valve actuator (10).

The first flow path (148) of the first flow means (140) includes an annular chamber (160) formed between the actuator head (20) and the main body (30), and the main port (164). The valve actuator (10) of claim 8, wherein the valve actuator (10) is fluidly connected to the annular chamber (160).

The first flow path (148) of the first flow means (140) includes an annular cavity (168) formed between the plunger (54) and the body (30), and the annular cavity (168). ) Is predetermined with respect to the main port (164) so as to open the main port (164) in a part of a process in which the plunger (54) moves between the first plunger position and the second plunger position. 11. The valve actuation device (10) according to claim 10, wherein the valve actuation device (10) extends at a predetermined length at the position.

The first flow path (148) of the first flow means (140) includes a passage (170) formed in the plunger (54), and the passage (170) is formed of the annular cavity (168). 12. A valve actuator (10) according to claim 11, which is fluidly connected to the valve actuator.

The first flow path (148) of the first flow means (140) includes a first check valve (174) seated in a bore (176) of the plunger (54), and the first check valve ( 174) includes an orifice (178) formed in fluid communication with the passage (170) and the first check valve (174) substantially restricts fluid flow in the direction toward the plunger cavity (130). 13. A valve actuation device (10) according to claim 12, having a non-open position and a closed position that substantially restricts fluid flow in the opposite direction.

The first flow path (148) of the first flow means (140) includes a stop member (180) disposed at a predetermined distance from the first check valve (174), and the stop member (180) 14. The valve actuator (10) of claim 13, further comprising an axially extending bore (184) that fluidly connects the orifice (178) of the first check valve (174) with the plunger cavity (130).

An internal combustion engine (12) comprising the valve operating device (10) according to any one of the preceding claims.